From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id D7F626B025F for ; Fri, 19 Jan 2018 10:27:53 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id b111so1429481wrd.16 for ; Fri, 19 Jan 2018 07:27:53 -0800 (PST) Received: from theia.8bytes.org (8bytes.org. [2a01:238:4383:600:38bc:a715:4b6d:a889]) by mx.google.com with ESMTPS id t7si1183246edc.248.2018.01.16.08.39.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Jan 2018 08:39:26 -0800 (PST) From: Joerg Roedel Subject: [PATCH 13/16] x86/mm/pti: Add an overflow check to pti_clone_pmds() Date: Tue, 16 Jan 2018 17:36:56 +0100 Message-Id: <1516120619-1159-14-git-send-email-joro@8bytes.org> In-Reply-To: <1516120619-1159-1-git-send-email-joro@8bytes.org> References: <1516120619-1159-1-git-send-email-joro@8bytes.org> Sender: owner-linux-mm@kvack.org List-ID: To: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Andy Lutomirski , Dave Hansen , Josh Poimboeuf , Juergen Gross , Peter Zijlstra , Borislav Petkov , Jiri Kosina , Boris Ostrovsky , Brian Gerst , David Laight , Denys Vlasenko , Eduardo Valentin , Greg KH , Will Deacon , aliguori@amazon.com, daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com, Andrea Arcangeli , Waiman Long , jroedel@suse.de, joro@8bytes.org From: Joerg Roedel The addr counter will overflow if we clone the last PMD of the address space, resulting in an endless loop. Check for that and bail out of the loop when it happens. Signed-off-by: Joerg Roedel --- arch/x86/mm/pti.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index a561b5625d6c..faea5faeddc5 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -293,6 +293,10 @@ pti_clone_pmds(unsigned long start, unsigned long end, pmdval_t clear) p4d_t *p4d; pud_t *pud; + /* Overflow check */ + if (addr < start) + break; + pgd = pgd_offset_k(addr); if (WARN_ON(pgd_none(*pgd))) return; -- 2.13.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org